Sorbent addition to the flue gas in the duct ahead of an ESP (Electrostatic Precipitator) is a process that is being used as a method to reduce mercury emissions from coal burning power plants. As currently practiced a sorbent, such as activated carbon, is added to the flue gas upstream of a particulate control device, either an electrostatic precipitator or fabric filter. If the sorbent is added ahead of a precipitator, mercury removal is limited to 60-70%, and higher rates of sorbent addition are needed to produce these levels of mercury removal than with baghouses. The inefficiency of this process results from the typical short flue gas residence time between the point of addition of sorbent and the ESP. This prior art process also mixes the sorbent with the collected fly ash, and the carbon in the ash can limit its use as an ingredient in concrete. If the sorbent is added to the flue gas after it leaves the ESP and before a “polishing” baghouse, better sorbent utilization is achieved and high mercury removal rates result, but the polishing baghouse can be an expensive item. An alternate approach that overcomes these disadvantages is described in this invention. The herein disclosed invention utilizes a two-stage electrostatic precipitator or electrostatically enhanced separator (EES), which is a particulate polishing device developed by EPRI. This two-stage electrostatic precipitator is a mechanically augmented electrostatic device that separates flue gas into two separate gas streams; a clean stream that contains very little ash and a bleed stream that contains most of the ash.